The cerebral microvessels isolated from brains of gerbils subjected to 15 minutes of complete cerebral ischemia and various periods of recovery had shown a selectively altered cerebral microvascular accumulation of monoamines in postischemia while the enzymes involved in the degradation of the amines were affected by ischemia and postischemia. The modified function of the isolated cerebral microvessels was closely related to the blood-brain barrier changes for monoamines observed in parallel studies.